I see two interesting considerations here:

1. Consider the referendums on statehood that Puerto Rico holds every once in a while. Those can essentially be boiled down to choosing between these two options: A) Being considered full-fledged citizens, being able to vote in federal elections, and having to pay federal taxes, vs. B) Maintaining the pride of nominal sovereignty, being exempt from federal taxes, and not being able to vote in federal elections.

Citizens of Puerto Rico have consistently opted for choice B. That suggests to me that in general, they consider the right to vote to be less valuable than the right to not pay taxes. So if one wanted to take away the right to vote for the less educated, they could be offered the same trade-off, and most would likely take it (of course, most well-educated people probably would too!). I still don't think I'd support it, but it's sort of an example where this choice has been given.

2. Which group is more intensively rent-seeking? I can see hypotheses for both ways. If in fact the less educated are less rent-seeking (if they act more emotionally, for instance), then policies could end up being worse. It's not clear to me which population is less rent-seeking though... like I said, I can see reasonable hypotheses for it going both directions